Re: [PATCH] virtio-pci: Fix the failure process in kvm_virtio_pci_vector_use_one()

[Cindy Lu <lulu@redhat.com>]

On Tue, Apr 16, 2024 at 8:30 PM Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Tue, 16 Apr 2024 at 13:29, Cindy Lu <lulu@redhat.com> wrote:
> >
> > In function kvm_virtio_pci_vector_use_one(), in the undo label,
> > the function will get the vector incorrectly while using
> > VIRTIO_CONFIG_IRQ_IDX
> > To fix this, we remove this label and simplify the failure process
> >
> > Fixes: f9a09ca3ea ("vhost: add support for configure interrupt")
> > Cc: qemu-stable@nongnu.org
> > Signed-off-by: Cindy Lu <lulu@redhat.com>
> > ---
> >  hw/virtio/virtio-pci.c | 19 +++----------------
> >  1 file changed, 3 insertions(+), 16 deletions(-)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index b138fa127a..565bdb0897 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -892,7 +892,7 @@ static int kvm_virtio_pci_vector_use_one(VirtIOPCIProxy *proxy, int queue_no)
> >      }
> >      ret = kvm_virtio_pci_vq_vector_use(proxy, vector);
> >      if (ret < 0) {
> > -        goto undo;
> > +        return ret;
> >      }
> >      /*
> >       * If guest supports masking, set up irqfd now.
> > @@ -902,25 +902,12 @@ static int kvm_virtio_pci_vector_use_one(VirtIOPCIProxy *proxy, int queue_no)
> >          ret = kvm_virtio_pci_irqfd_use(proxy, n, vector);
> >          if (ret < 0) {
> >              kvm_virtio_pci_vq_vector_release(proxy, vector);
> > -            goto undo;
> > +            kvm_virtio_pci_irqfd_release(proxy, n, vector);
>
> Are you sure this is right? The kvm_virtio_pci_irqfd_use()
> just failed, so why do we need to call
> kvm_virtio_pci_irqfd_release() ?
>
> thanks
> -- PMM
>
This version should be correct.  when kvm_virtio_pci_irqfd_use() fail
we need to call kvm_virtio_pci_vq_vector_release() and
kvm_virtio_pci_irqfd_release()
but for kvm_virtio_pci_vq_vector_use fail we can simple return,

in old version there is a error in failure process.
while the kvm_virtio_pci_vq_vector_use fail it  call the
kvm_virtio_pci_irqfd_release,but at this time this is irqfd
is not using now

I have do the qtest and sanity test for this patch
Thanks
cindy